1. Field of the Invention
This invention relates generally to a speech synthesizer and more specifically to such a synthesizer which features a simple arrangement and hence is highly suited for being used in large scale integration (LSI).
2. Description of the Prior Art
Various discrete-time models for speech production have been proposed, one of which is disclosed in a book entitled "Digital Processing of Speech Signals", pages 98-106, written by Lawrence R. Rabiner and Ronald W. Schafer, and published by Prentice-Hall, Inc., Englewood Cliffs, N.J. According to the general discrete-time model for speech production disclosed in the above-mentioned book, by switching between voiced and unvoiced excitation generators it is possible to model the changing modes of excitation. However, this known discrete-time model does not suggest any concrete circuit arrangement for achieving the same. Further, this prior art requires the provision of two separate generators, viz., an impulse train generator and a random noise generator both coupled to a voiced/unvoiced switch. Consequently, the prior art has encountered the problem that it is unsuitable for manufacture utilizing LSI techniques.